This invention relates primarily to technology for providing an alternative visual interface of an intelligent mobile telephone, a smart phone, a personal digital assistant (PDA) or like device having a display, a processor, and a mobile device operating system with a graphical interface that in the present invention can be interdicted. An example is the Microsoft Windows Mobile operating system used in cellular telephones and PDAs having a processing unit capable of supporting the operating system. Smart phones herein encompass hand-held small mobile computers with some telecommunication capability and that are functional as telephones and that have primary constraints on size, weight and portability. Such constraints, as a consequence, impose constraints on power, display resolution and data entry capabilities, as compared with portable laptop computers, desktop computers and the like. For the purposes of this invention, there is no distinction to be drawn between smart phones and handheld personal digital assistants, so hereinafter the terms may be used interchangeably.
Smart phones are becoming a primary personal data assistant, since they can provide a host of functions integrated into a single handheld, pocket-sized computer unit, including telephone, email, messaging, internet access, calendar, calculator, task managers, word processor, still and video camera, clock and alarm clock, as well as an audio and video entertainment center, game console, GPS, and a host of other computer-based functions. A smart phone can even serve as a flashlight. However, the major strength of the smart phone—its extreme portability—is also a major weakness. Because of its inherent small size, the smart phone is not able to provide a display or a fully functional keyboard and pointing device useable for office applications such as word processing, spreadsheet programs, email clients, etc. These constraints limit the potential versatility of the smart phone.
A class of hardware and software products exist to address the so-called KVM (keyboard-video-mouse) interface problem. Unlike a conventional KVM application wherein a fixed asset is made accessible at a remote location, this invention relates to enhancing limited capabilities of a typical mobile asset in a local environment. Extended keyboards have been developed for selected personal digital assistants (PDAs). Software has been developed to extract data from smart phones for use on the mobile or desktop computers. Hot sync capability provides backup but does not necessarily provide a complete mirror of the content of mobile device. Screen copier programs copy phone display images to desktop computer screens, but do not enhance phone display resolution.
Display technology has also been developed that allows multiple display drivers to co-exist on certain smart phones and to allow smart phones to connect and drive larger displays. An example is described in the documentation of the tools known as Microsoft CE SDK, in which the concept of a secondary driver is defined as a co-resident auxiliary driver that is known to the operating system when installed. In one such method, a conventional secondary display driver is installed in the operating system to create larger resolution displays for use with a connected projection system. In this scheme, applications that wish to take advantage of the secondary driver must have specialized knowledge related to the secondary display driver and be written specifically for use with the secondary display driver. Other applications such as word processors, spreadsheets, email clients, and presentation applications which are written to interact with the default primary display driver and have no specific knowledge related to the secondary display driver are unable to take advantage of the features of the secondary driver. In another prior art method, the original display driver is replaced with a new display driver with enhanced capabilities. An alternate display driver is connected to the operating system's graphical display subsystem in an identical fashion to the original display driver with the desirable effect that applications written for the default primary display driver will be able to display their information in a larger format without modification or special knowledge. The significant disadvantage of this method is that when the user wishes to switch from the original to the alternate display driver or vice versa, a series of installation or re-installation steps, including a complete system re-initialization (re-boot), must be executed. These steps, which include closing and restarting applications, services, and device drivers, are inconvenient, time consuming and prone to error.
One technique that has been developed to overcome the re-initializing requirement is the so-called screen scraping technique. According to this technique, an application is installed that gains access to the primary display driver display buffer and periodically copies its content to a network protocol for remote viewing. One disadvantage is that the display resolution remains unchanged. Another disadvantage is that this technique is noticeably slow to execute. Still another disadvantage is that periodic sampling may result in missing content. This process is inefficient and can leave an unsatisfactory visual impression and noticeably slow display of images, particularly video images. In another method, the default primary display driver is replaced with another display driver that typically has a higher resolution while remaining connected to the original, lower resolution display device. Thus, even though applications may present a larger image to the alternate display driver, only a selectable portion of the large image is visible to the user at any given moment.
What is needed is a technique to seamlessly provide an alternative video display for handheld smartphones or PDAs.